The VHCT573A is an advanced high speed CMOS octal latch with 3-STATE output fabricated with silicon gate CMOS technology. It achieves the high speed operation similar to equivalent Bipolar Schottky TTL while maintaining the CMOS low power dissipation. This 8-bit D-type latch is controlled by a Latch Enable input (LE) and an Output Enable input (OE). When the OE input is HIGH, the eight outputs are in a high impedance state. Protection circuits ensure that 0V to 7V can be applied to the input and output (Note 1) pins without regard to the supply voltage. This device can be used to interface 3V to 5V systems and two supply systems such as battery back up. This circuit prevents device destruction due to mismatched supply and input voltages.